Efficient Electrocatalytic Hydrogen Evolution Reaction Research Articles

Construction of Pt Single-Atom and Cluster/FeOOH Synergistic Active Sites for Efficient Electrocatalytic Hydrogen Evolution Reaction

Construction of Pt Single-Atom and Cluster/FeOOH Synergistic Active Sites for Efficient Electrocatalytic Hydrogen Evolution Reaction

Synthesis of M-NiS/Mo2S3 (M=Co, Fe, Ce and Bi) nanoarrays as efficient electrocatalytic hydrogen evolution reaction catalyst in fresh and seawater

Electrolysis of water for production of hydrogen has become one of the most fascinating methods to relieve the energy crisis and environmental pollution. In this paper, a series of M-NiS/Mo2S3 (M = Co, Fe, Ce and Bi) materials was in situ grown on Ni foam through a two-step hydrothermal process, and the synthesized Co–NiS/Mo2S3 material present excellent hydrogen evolution reaction (HER) properties. Under an alkaline condition of 1 M KOH, Co–NiS/Mo2S3 requires only overpotential of 142 mV to achieve a current density of 10 mA cm−2, and using Co–NiS/Mo2S3 as both cathode and anode, only the potential of 1.574 V is required to drive a current density of 50 mA cm−2, with a relatively good durability over 15 h. Density functional theory (DFT) analysis show that the ΔGH* of Co–NiS is closer to 0 and its density of states near the Fermi energy level is higher, suggesting that Co–NiS improves the electrical conductivity of Co–NiS/Mo2S3 and plays a significant catalytic action. This work proposes novel insights for the future exploration of novel sulfur-based composite electrocatalysts with excellent HER performance.

Facile fabrication of MoS2 and MoSe2 layered structures on Mo foil for the efficient photocatalytic dye degradation and electrocatalytic hydrogen evolution reaction

The rapidly growing necessity for sustainable materials in fields such as energy, environmental science, and medicine, two dimensional-based photo- and electro-catalysts has obtained mounting consideration. A simple methodology was employed to fabricate MoSe2 and MoS2 layered structures on flexible Mo foil as heterogeneous catalysts for the electrocatalytic hydrogen evolution reaction (HER) and the photocatalytic decolorization of chromic red (CR) and methylene blue (MB) dyes. The structural characteristics confirm the formation of the multi-layer thick MoSe2 and MoS2 nanofilms. The toxic MB and CR dyes were rapidly and effectively decolorized in polluted water by the photocatalysts within 30 min of UV-light irradiation. The fabricated layered structures exhibited favorable HER electrocatalytic activities along with low overpotentials, small Tafel slopes, and excellent 24-h stability performances. The strong catalytic behavior of these structures fabricated on Mo foil in relation to the HER reaction and the dye decolorization process make them suitable candidates for the catalyst industry.

ZnO monolayer-supported single atom catalysts for efficient electrocatalytic hydrogen evolution reaction.

Hydrogen is identified as one of the most promising sustainable and clean energy sources. The development of a hydrogen evolution reaction (HER) catalyst with high activity is essential to meet future needs. Considering the novel advantages of two-dimensional materials and the high catalytic activity of atomic transition metals, in this study, using density functional theory calculations, the HER on a single transition metal (10 different TM atoms) adsorbed and doped ZnO monolayer (ZnO-m) has been investigated. The Volmer-Tafel reaction mechanisms and strain engineering of the three best HER catalysts are also discussed. The results show that Pt@ZnO-m, Co-doped ZnO-m and Ir-doped ZnO-m with high stability all have a smaller absolute H adsorption free energy than Pt, and the optimal value of Pt@ZnO-m is -0.017 eV. The calculation of the reaction energy barriers shows that the Volmer-Tafel step is favorable. Co@ZnO-m and Ir@ZnO-m have high HER activity, the widest pH range, and acid-alkali resistance. Pt@ZnO-m and Co-doped ZnO-m maintain excellent HER performances in the strain range of -4% to 4%.

Pt nanoparticles anchored by oxygen vacancies in MXenes for efficient electrocatalytic hydrogen evolution reaction.

The improvement of the hydrogen evolution reaction (HER) performance of nanomaterials is associated with the interfacial synergistic interaction and their hydrogen adsorption kinetics. Nevertheless, it is still a challenge to accelerate the proton transfer and optimize the HER kinetics by constructing Pt-supported heterostructures based on the hydrogen spillover phenomenon. Herein, oxygen vacancies on the surface of MXene nanosheets were constructed via a high-temperature annealing method, which was employed to anchor/stabilize Pt nanoparticles and fabricate a Pt/MXene heterostructure. EPR and XPS analyses verified the presence of oxygen vacancies, which could enhance the intrinsic HER activity of the MXene. The HER catalytic performance was investigated by taking into account the surface structure of the MXene affected by the annealing temperature, the concentration of Pt and the number of deposition cycles. Electrochemical results showed that Pt/MXene with higher utilization of Pt was obtained at 900 °C and 0.05 mgPt mL-1. The 0.05-Pt/MXene-900 obtained at deposition of 60 cycles in 0.5 M H2SO4 solution exhibited the optimized HER activity. The overpotential was 22 mV at a current density of 10 mA cm-2 and the Tafel slope was 42.41 mV dec-1. Furthermore, the accelerated HER kinetics was mainly due to the electron trapping ability of the MXene, small particles of Pt, as well as the enhanced charge transfer between the oxygen vacancies of the MXene and Pt. This strategy for constructing Pt-supported heterostructures based on the vacancy anchoring effects provides new ideas for the design of well-defined electrocatalysts toward the HER.

Modulating the electronic structure of VS2via Ru decoration for an efficient pH-universal electrocatalytic hydrogen evolution reaction.

High-efficiency water electrolysis over a broad pH range is desirable but challenging. Herein, Ru-decorated VS2 on carbon cloth (Ru-VS2/CC) has been in situ synthesized, which features the regulated electronic structure of VS2 by introducing Ru. It is remarkable that the optimal Ru-VS2/CC displays excellent electrocatalytic hydrogen evolution activity with overpotentials of 89 and 87 mV at -10 mA cm-2 in 0.5 M H2SO4 and 1.0 M KOH, respectively. Theoretical calculations and electrocatalytic measurements have demonstrated that introducing Ru induces an enhanced charge density around the Fermi level, facilitating charge transfer and speeding up the electrocatalytic HER kinetics. The Gibbs free energy of the hydrogen intermediate (ΔGH*) of Ru-VS2/CC (0.23 eV) is much closer to zero than that of pure VS2 (0.51 eV) and Ru (-0.37 eV), demonstrating an easier hydrogen adsorption and desorption process for Ru-VS2/CC. The more favorable ΔGH*, differential charge density and the d-band center endow Ru-VS2 with enhanced intrinsic electrocatalytic activity. This study presents a feasible strategy for enhancing electrocatalytic HER activity by the regulation of the electronic structure and the rational integration of dual active components.

Doping Ni into CoB achieves surface reconstruction to promote efficient electrocatalytic hydrogen evolution reaction

The effective advancement of skilled transition metal electrocatalysts is crucial for promoting the hydrogen evolution reaction (HER) in the process of water splitting. In this context, the integration of nickel (Ni) transition metal atoms into cobalt boride (CoB) is achieved through an electrochemical deposition approach, yielding a remarkably active electrocatalyst termed Ni@CoB for HER. At 10 mA cm−2, the HER overpotential is 63 mV with a Tafel slope of 64.73 mV dec-1. After 50 h of stability testing, there was no significant current decay observed. By employing material characterization techniques and DFT calculations, it has been shown that the incorporation of Ni leads to a surface reconstruction of CoB, thereby decreasing surface aggregation. The catalyst exhibits a uniform spherical porous structure, facilitating enhanced electron transfer. The doped Ni atoms form a bimetallic synergistic effect with Co atoms, not only increasing the stability of interatomic covalent bonds but also enhancing reaction kinetics. This study illuminates the influence of incorporating transition metal atoms into CoB on the activity of HER, presenting a promising strategy for designing high-performance catalysts for alkaline hydrogen evolution.

Coupling NiSe2 Nanoparticles with N-Doped Porous Carbon Enables Efficient and Durable Electrocatalytic Hydrogen Evolution Reaction at pH Values Ranging from 0 to 14

Coupling NiSe₂ Nanoparticles with N-Doped Porous Carbon Enables Efficient and Durable Electrocatalytic Hydrogen Evolution Reaction at pH Values Ranging from 0 to 14

The cactus bulb-shaped metal-S-C/N nanoparticles supported by highly conductive channels for efficient electrocatalytic hydrogen evolution reaction

Accelerating electron transfer and exposing active sites are key factors that could improve electrocatalytic hydrogen evolution reaction (HER). In this study, Co3S4-Ni3S2-C/N, the cactus bulb-shaped nanoparticles based on metal-organic frameworks (MOFs), were successfully prepared. The catalyst requires only 101 and 227 mV overpotential to reach current densities of 20 and 100 mA cm−2, respectively, in 1 M KOH. The high catalytic activity is attributed to the confinement effect achieved by introducing 2-aminoterephthalic acid as a precursor, allowing the catalyst to have a small particle size and fully exposed metal active sites. Moreover, the catalyst has a highly conductive metal-S-C/N channel that effectively reduces the intrinsic charge transfer resistance of the catalytic electrode, improves its conductivity, and modulates the electron density at the metal active site. Furthermore, compared to other crystal planes, the exposed (111) crystal plane of Co3S4 provides the most octahedral coordination of high spin state Co3+, which is highly catalytically active. This makes it the dominant crystal plane for catalysis. Through spatial confinement effect to limit metal sulfide particle size and introducing an organic backbone to create highly conductive metal-S-C/N channels, our study provides a general approach to developing highly active catalytic materials.

Efficient Electrocatalytic Hydrogen Evolution Reaction on CuO Immobilized Stainless‐Steel Electrode Prepared by the SILAR Method

AbstractThe development of cost‐effective and efficient catalysts for the hydrogen evolution reaction (HER) has been a subject of intense research for sustainable and clean energy in recent decades. For this purpose, CuO‐modified stainless steel (CuO‐SS) electrode was fabricated to attain HER in acidic media. Here in, CuO film was fabricated on a stainless steel (SS) surface following successive ionic layer adsorption and reaction (SILAR) method. A 60‐cycle CuO modification resulted in enhanced HER activity compared to the bare SS or CuO electrode with an average 99 % Faradic efficiency. Based on the Electrochemical Impedance Spectroscopy (EIS), at an HER potential, the bare SS electrode exhibited charge transfer resistance of 24.7 Ω whereas CuO‐SS electrode exhibited 6.47 Ω only. The overpotential was calculated to be 154 mV at the CuO‐SS electrode regarding HER. The results have significant implications for the development of cost‐effective and efficient electrocatalysts for hydrogen production.

TiO2 nanotubes modified with cobalt oxyphosphide spheres for efficient electrocatalytic hydrogen evolution reaction in alkaline medium

Electronic and surface modulation through coupling between oxygen and phosphorous in cobalt oxyphosphide (CoOP) is identified as an effective approach to enhancing the electrocatalytic hydrogen evolution reaction (HER) in an alkaline medium. This work demonstrates a one-step and safe electrodeposition method to modify the surface of ordered titania nanotubes (TNTs) with CoOP spheres. The effect of electrodeposition charge density, pH of the electrodeposition bath, and presence of citric acid on the electrocatalytic HER performance of CoOP-modified TNTs was investigated. The Ti/TNTs/CoOP electrode requires only 130 mV overpotential to deliver 10 mA cm−2 in a 1.0 M KOH electrolyte. The Tafel slope is estimated to be 72.5 mV dec−1. Both the HER performance and Tafel value of Ti/TNTs/CoOP are superior to CoOP deposited on bare Ti foil (165 mV and 78.4 mV dec−1), FTO (185 mV; 88.1 mV dec−1), and glassy carbon (214 mV; 93 mV dec−1). The electrochemically active surface area (ECSA) and impedance spectroscopy findings revealed that the synergistic coupling between the CoOP and TNTs enhances the surface area and density of accessible active sites while reducing the charge transfer resistance at the electrode/electrolyte interface. Such a synergistic effect is ascribed to the effective electronic interaction between CoOP and TNTs, and the faster electron transfer kinetics because of the unidirectionality of the 1-D TNTs.

Modulation of electronic density states of carbon atom via multifaceted Cu doped Co2P particle for robust and efficient electrocatalytic hydrogen evolution reaction in aqueous acidic medium

Development of Pt free catalyst for hydrogen evolution reaction (HER) having both superb efficiency and sound stability is a key challenge in the field of alternate fuel production. Herein, we have reported Cu doped multifaceted Co2P particles incorporated on expanded graphite synthesized via solvothermal method, and studied its catalytic activity. The composite catalyzes the evolution of H2 efficiently with a potential value 81 mV to achieve the benchmark current density of 10 mA cm-2 and a Tafel slope value of 113 mV dec‑1 coupled with a remarkable long-term stability for 21.6 h. Our experimental analysis provides strong evidence that the multifaceted Cu doped Co2P could work in concert with carbon atoms of the expanded graphite (EG) that leads in the changing of the energy states of nearby carbon atoms of the metal phosphide particle which is also in well agreement of our theoretical calculation. The lower contact electrical resistance of EG have significant impact in endowing fast electron transfer to the catalytic active sites and the aid of catalytic performance. The specific morphology of the catalyst hints at increased surface area and overall exposed active sites to bestow the catalytic performance. The study suggests that the energetically modulated carbon atoms can act as a fine active site for HER.

Regulating Hollow Carbon Cage Supported NiCo Alloy Nanoparticles for Efficient Electrocatalytic Hydrogen Evolution Reaction.

The NiCo alloy is one of the most promising alternatives to the noble-metal electrocatalysts for the hydrogen evolution reaction (HER); however, its performance is largely restricted by insufficient active sites and low surface area. Here, we fabricated a hierarchical hollow carbon cage supported NiCo alloy (denoted as HC NiCo/C) and a bulk NiCo alloy (denoted as NiCo) by reduction of a partially ZIF-67 etched ZIF-67@NiCo-LDH (LDH = layered double hydroxide) precursor and a fully ZIF-67 etched NiCo-LDH precursor, respectively. The as-prepared HC NiCo/C, in which the Ni29Co71 alloy nanocrystals with an average 6 nm size were encapsulated in graphitic carbon layers, provided a vastly increased electrochemically active surface area (ca. 13 times than the NiCo) and abundant catalytic active sites, which resulted in a higher HER performance with an overpotential of 99 mV than the 198 mV for NiCo at 10 mA cm-2. Detailed experimental results suggested that only the HC NiCo/C possessed the active alloy surface composed of unsaturated Ni0 and Co0 atoms, and both the metal-support interaction and alloying effect influenced the electronic structure of Co and Ni in HC NiCo/C, whereas the NiCo exhibited pure Ni surface. Theoretical calculations further revealed the Ni29Co71 alloy surface in HC NiCo/C possessed the appropriate adsorption energy of the intermediate state (adsorbed H*). This work provided new insight into the construction of the stable small-sized bimetallic alloy nanocatalysts by regulating the reduction precursors.

Infrequent Cubane-Like Chromium Sulfide Cluster with σ-Donor Ligands with Efficient Electrocatalytic Property Toward Hydrogen Evolution Reaction.

The exploitation of efficient and economical electrocatalysts for hydrogen evolution reaction (HER) is of exceeding interest in renewable clean-energy technologies. Herein, the facile solvothermal reaction of S and chromic acetate in ethylenediamine (en) achieved a novel organic hybrid chromium sulfide [Cr4(μ3-S)4(en)4(SH)4]·0.25H2O (1), which offers a new type of antiferromagnetic cubane-like chromium sulfide cluster with σ-donor en ligands. 1 was utilized in combination with Ni nanoparticles and porous Ni foam (NF) to fabricate a Ni/1/NF electrode as an efficient cathodic catalyst, indicating excellent electrocatalytic property toward HER.

Dual Function of Hypo-d-electronic Transition Metals in the Brewer Intermetallic Phase for the Highly Efficient Electrocatalytic Hydrogen Evolution Reaction in Alkaline Electrolytes

Reported are the synthesis, material characterization, and electrocatalytic hydrogen evolution reaction (HER) in acid and alkaline electrolytes for the Brewer intermetallic phase, Nb6Co7 and Mo6Co7. It was realized that the overpotential at a current density of 10 mA/cm2 (η10) for Nb6Co7 (η10 = 62 mV) and Mo6Co7 (η10 = 143 mV) are both much lower than that of using a single Co metal (η10 = 253 mV) in alkaline electrolytes. The enhancement of electrocatalytic HER activity of Nb6Co7 and Mo6Co7 can be attributed to the hypo-hyper-d-electronic interaction between Nb/Mo and Co elements. Based on the result of density functional theory calculation, alloying between Nb/Mo and Co elements will increase the antibonding state population of the Co-Co bond near the Fermi level (EF), which induces the synergistic effect to influence the adsorption energy of the H atom (ΔGH) on the surface of Nb6Co7 and Mo6Co7. Moreover, the role of the Nb element is not only a simple electron donor but is also an anchor position for the OH molecule (i.e., dual function) due to the bonding character of the Nb-Co bond near EF. It can reduce the OH position effect as well as the activation energy for water dissociation, which rationalizes the high and robust HER performance of Nb6Co7 to that of commercial Pt/C (η10 = 67 mV) in alkaline electrolytes.

Activating RuOCo Interaction on the a-Co(OH)2 @Ru Interface for Accelerating the Volmer Step of Alkaline Hydrogen Evolution.

The state-of-the-art active hydrogen evolution reaction (HER) catalysts in acid electrolytes generally lose considerable catalytic performance in alkaline electrolytes mainly due to the additional water dissociation step. Designing composite materials is an effective strategy to accelerate alkaline water electrolysis by optimizing the electronic structure of materials. Here, different phases of Co(OH)2 -supported Ru clusters (α/β-Co(OH)2 @Ru) are prepared for enabling a highly efficient electrocatalytic HER performance in alkaline solution. The prepared α-Co(OH)2 nanosheets facilitate the loading of uniform and high-density Ru clusters and the formed highly active RuOCo bonds at the interface. The synergistic interaction endows the hybrid catalyst with low overpotential of 33mV at 10mA cm-2 . Moreover, the homemade anion exchange membrane water electrolysis cell based on α-Co(OH)2 @Ru affords a cell voltage of 2V to drive a current density of 270mA cm-2 and performs stably during continuous operation for over 100h. Density functional theory calculations demonstrate that active RuOCo bonds in α-Co(OH)2 @Ru optimize the energy barriers for H2 O dissociation and OH- desorption to facilitate the Volmer reaction step. This work offers a strategy for designing interfacial chemical bonds for high electrocatalytic activity.

A computational study of design and performance investigation of Ni-based electrocatalysts for efficient electrocatalytic hydrogen evolution reaction

Theoretical calculations were used to design Ni-based catalysts for efficient electrocatalytic HER.

ZIF – 67 derived hybrid CuCo2S4@MoS2 catalyst for efficient electrocatalytic hydrogen evolution reaction

Developing hybrid metal sulfide electrocatalyst with excellent hydrogen evolution reaction (HER) catalytic performance and stability is vital to its commercial applications. Herein, hybrid CuCo2S4@ MoS2 catalysts were designed with CuCo2S4 synthesized by using ZIF-67 as a template and externally decorated with MoS2. The hybrid catalysts (denoted as C@M-0.5, C@M ​− ​1, C@M ​− ​2) show improved catalytic activity than those of MoS2 and CuCo2S4 due to large surface area and the interface between nanoflower-like MoS2 and three-dimensional interconnected lamellar stacked CuCo2S4, which boost charge transport capability and improve the HER kinetic process. The influences of different ratio of CuCo2S4 to MoS2 on the electrocatalytic activity are investigated in detail. Specifically, C@M ​− ​1 exhibit the best HER performance with an overpotential of 143 ​mV@ 10 ​mA/cm2, a Tafel slope of 45.2 mV/dec and satisfactory long-time stability. This work rationally designs hybrid CuCo2S4@MoS2 catalyst to preserve the merits of using the ZIF-67 as a template and make use of the synergistic coupling effects between CuCo2S4 and MoS2, which can be extended to synthesize other catalysts in different energy conversion fields.

Cu/Cu3P@CNT Flexible Film Electrode for Highly Efficient Electrocatalytic Hydrogen Evolution in Alkaline Solution

AbstractGlobal warming and the global energy crisis are worsening owing to the increasing consumption of fossil fuels; thus, there is a need to explore renewable and clean energy sources. The energy conversion efficiency of water electrolysis – an important and feasible means to obtain green hydrogen energy – can be improved by developing catalytic electrode materials with high activity and low overpotential. Herein, low‐temperature phosphating of copper deposited on flexible carbon nanotube (CNT) films was conducted to fabricate high‐performance Cu/Cu3P@CNT electrocatalysts for the hydrogen evolution reaction (HER). The optimal conditions for the preparation of catalytic electrodes were determined by adjusting the electrodeposition time. Owing to the porous CNT framework and the heterostructure of the Cu3P/Cu nanoparticles, the Cu/Cu3P@CNT exhibited long‐term stability and highly efficient catalytic HER in an alkaline electrolyte with an overpotential of only 77 mV at 10 mA cm−2. This study provided a facile strategy for designing inexpensive and efficient electrocatalytic HER systems using highly active transition metal phosphides heterostructures and CNT materials.

Ruthenium doped commercial carbon cloth for efficient electrocatalytic hydrogen evolution reaction

The heterogenous electrochemical catalyst of activated carbon cloth coupled with Ru doping was fabricated via a facile hydrothermal method. The obtained activated carbon cloth coupled with Ru catalyst possesses outstanding hydrogen evolution reaction performance even superior than 40 % Pt/C catalyst in alkaline system. • Commercial carbon cloth was activated via facile hydrothermal process for the first time. • The Ru atoms anchored on carbon cloth act as the new active centers. • Ru/CC exhibited excellent HER activity and strong stability in alkaline solution. • Low overpotential of 24 mV and Tafel slope of 51.5 mV dec −1 was delivered at 10 mA cm −2 . Ru atoms are doped on the surface of commercial carbon cloth (Ru/CC) through a simple and facile hydrothermal process and the catalytic inert surface of CC is activated. The activated Ru/CC exhibit excellent HER electrocatalytic activity in 1 M KOH solution. The Ru/CC-0.1 catalyst has a small overpotential of 24 mV at 10 mA cm −2 and low Tafel slope of 51.5 mV dec −1 .